Improvement in the art of preserving wood



A. B. TRIPLER. v The Art of Preserving Wood.

No. 208,649. Patented Oct. 1, 1878.

NPETERS, PHOTO-LITNDGRAPHER WASHINGTON. D c.

UNITED STATES PATENT OEEIcE.

AROHIBALD E: TRIPLER, on NEW YORK, N. Y.

IMPROVEMENT IN THE ART OF PRESE-RVING WOOD.

Specification forming part of Letters Patent No. 208,649, dated October1, 1878 application filed March 16, 1879.

To all whom it may concern:

Be it known that I, ARCHIBALD B. TRIPLER, of the city and county of NewYork, in the State of New York, have invented a new and usefulImprovement in the Art of Preserving Wood, of which the following is aspecification:

This invention relates to the curing and dryin g of wood under pressureby means of heat.

Wood has thus been dried in heated molds, and it has been proposed tocreate and maintain the required pressure by means of air or gas pumpedinto the drying-chamber, while the required heat is obtained by means ofsteam-coils.

In my varied experience with air and steam, as employed in differentarts, I have observed the superiority of the latter as a vehicle forheat, especially as regards the retention. of heat and its uniformdiffusion, and as a medium of pressure, owing to its less elasticity,850. These observations, together with my experience in seasoning andpreserving wood, and discoveries touching the latter, have led me todevise my present process and apparatus for curing and drying wood underpressure by means of superheated steam, as an improvement on thatdescription of wood-preserving process and apparatus in which air or gasis employed as the vehicle of heat.

My said invention consists more particularly, first, in curing anddrying wood under pressure in a cylinder, or its equivalent, bysubjecting the wood to a current of superheated steam kept at sufficientpressure and temperature by the continued introduction of superheatedsteam, while a sufficient discharge is permitted to carry off anymoisture which may result from evaporation or partial condensation;secondly, in a preliminary application of heat by means of asteam-jacket to prepare thecylinder and wood for the superheated steam,anda concluding current of air or superheated steam through the body ofwood to carry oit' all surface humidity therefrom, in combination withthe said application of superheated steam; thirdly, in the combinationof apparatus hereinafter described for curing and drying wood by this oran analogous process.

Besides the specific effects above enumerated, I am enabled by my saidinvention to accomplish a great simplification of the operation, and amaterial reduction of the first cost and running expenses of theapparatus as compared with others now in use, while the wood isperfectly protected against checking and warping, and the albuminous,gummy, and resinous portions of the sap are difl'used and solidified inthe pores, so as to render the dried wood very solid, and to destroy thefermentative cause of decay in the most rapid and efficient manner.

Figure l ofthe accompanying drawings represents a side elevation of mysaid apparatus, partly in vertical section. Fig. 2 is an end view orfront elevation of the cylinder in which the wood is treated.

The improved apparatus for preserving wood consists, as shown, of ahorizontal cylinder, 0, adapted to receive the wood and sustain therequired pressure, a steam-jacket, J, for heating the cylinder and itscontents, preliminarily and supplementarily, one or more superheaters, SS", through which steam may be passed to the interior of the cylinder,and a rotary fan, F, discharging into the rear end of the cylinder, withtheir connections and appurtenances, as hereinafter mentioned.

The front end of the cylinder 0 is preferably not jacketed, but may beinsulated, as may also the jacket, by means of asbestus cement, or anypreferred non-conductor, to prevent loss of heat by radiation. To thisend of the cylinder a door, (I, a thermometer, t, and a pressure-gage,g, are applied in suitable manner. A pipe, 11, connects the interior ofthe jacket J with a steam-boiler, and steam-pipes p p connect theinterior of the cylinder 0 with the same or another boiler or boilers ofthe required capacity through the medium of coils c in the superheaters.Additional pipes, 19 12 provide for the discharge of water ofcondensation from the jacket J and from the cylinder 0, respectively,and a pipe, 12 provides for a continuous discharge from the cylinder.Another pipe, 19 connects the interior of the cylinder with the fan I.All the pipes are provided with suitable valves or stop-cocks, s, andthe jacket J is provided, further, with a safety-valve, r.

lhe details of the respective parts of the apparatus form no part ofthis invention; but they may be of any suitable or approvedconstruction, and mechanical equivalents of the respective parts may besubstituted, it preferred.

The escape-pipes p p may be combined, if preferred, a petcocksubstituted for the pipe 1), the fan F and its pipe p dispensed with,and other like modifications be made, without departing from the scopeof the invention as herein defined.

The proportions and arrangement of the parts are, of course, variable tosuit different circumstances and requirements.

The improved process of preserving wood as conducted in this apparatusis as follows: Supposing steam to be up in the boiler or boilers whichsupply the apparatus, fire started in the superheaters S S the fan Fadapted to receive motion, and all the valves a closed, a quantity ofwood is introduced, on a truck or otherwise, into the cylinder 0 throughthe door d, and the latter is closed. The valve 8 in the pipe 1) is nowopened, and steam is admitted into the jacket J until a pressure ofabout fifteen pounds to the square inch is attained. The safety-valve 1;may be weighted to determine this pressure, which will be kept upthroughout the operation. The principal object is a preliminaryelevation of the temperature of the cylinder and the wood therein. Thispreliminary heating prepares the cylinder and wood for greater heat, andprevents the loss of superheated steam by condensation. After thecylinder and wood are heated up to the heating capacity of the steam inthe jacket, as indicated by the thermometer, the valves in the pipes 12are opened, and superheated steam is admitted into the cylinder until atemperature of about 300 Fahrenheit and a pressure of about one hundredpounds to the square inch are indicated by the thermometer t and gage g.The pressure is that in the boiler or boilers, and is guarded by thesafety-valves on the latter, and increased or diminished at this point.The temperature is regulated by means of the fires in thesuperheaters,which also dry the steam, so as to increase itsefl'ectiveness as a drying agency. The object of the pressure is to keepthe fibers of the wood intact against the tendency to cheek and warpunder the intense heat. The latter, after expelling the gaseous andwatery elements of the contents of the pores, diffuses the more solidparticles, and finally solidifies the albuminous, gummy, and resinousportions of the sap within the pores, so as to solidify the wood whilecuring and drying the same. These results are accomplishedsimultaneously and by the same means, by employing superheated steam asthe curing and drying atmosphere. When the said pressure of about onehundred pounds to the square inch is obtained, the valve in the pipe 1)is opened or partially opened, so as to allow the superheated steam toescape in the same proportion as it is admitted, so as to keep up thesame pressure, and at the same time a continuous circulation through thewood to be cured. This carries off any moisture which may result fromevaporation, and prevents the steam within the cylinder from becomingmoist by condensation or partial condensation, and thus greatlyfacilitates and hastens the desired result.

The valve in the pipe 19 may be opened from time to time to dischargewater of condensation. The valve in the pipe 19 will not require to beopened for this purpose after the escape 'pipe p is opened.

Afterasufficient time has elapsed for the solidifyingof the particles inthepores of the wood, which will vary somewhat, and must be determinedby experience in treating wood of different kinds, the supply ofsuperheated steam is shut off by closing the valves in the pipes 11 andthat within the cylinder is allowed to escape through the pipe 19 Thedoor d is then opened; but before removing the wood, and while the steamis still held in the jacket, the valve in the pipe 12 is opened and thefan F is started, so as to cause a current of air to pass through thebody of wood in the cylinder. This is kept up until all surface humidityhas passed off, after which the steam is shut off from the jacket andthe fan is stopped. A blast of superheated steam may be substituted forthe air-blast in some cases, and the fan thus dispensed with.

I am aware that wet steam has been commonly used in treating wood, andIdisclaim the same. \Vet steam or ordinary steam, as thus employed,softens the wood, and is preliminary to drying, whereas the latter isaccomplished under pressure by the use of superheated steam, as hereinset forth.

It has also been proposed to employ superheated steam in connection withchemical treatment, but never so as to maintain a curing temperature andpressure thereby in the manner herein specified.

I also disclaim drying wood under pressure in an atmosphere of air orgas, the latter being at rest in the cylinder or drying-chamber andheated therein.

The following is what I claim as new and desire to secure by LettersPatent, namely:

1. The curing and drying of wood under pressure by means of anatmosphere of superheated steam introduced into a drying-chamber anddischarged therefrom simultaneously after the required pressure isobtained, substantially as specified, so as to keep up the said pressurea sufficient time, and at the same time cause a current through the bodyof the wood to carry of? moisture and prevent condensation, as hereinset forth.

2. The process herein described of curing and drying wood in a cylinderor its equivalent, consisting in heating the cylinder and the woodtherein by low-pressure steam in a jacket, then introducing superheatedsteam into the cylinder until a pressure of about one hundred pounds tothe square inch is obtained, then permitting the superheated steam J,and one or more superheaters, S S with their to escape in the sameproportion as a fresh appurtenances, substantially as herein shownsupply is admit-ted, and finally discharging and described, for curingand drying wood the superheated steam, and blowing air or suunderpressure.

perheated steam through the body of the A. B. TRIPLER. wood to carry offthe surface humidity from WVitnesses: the latter, substantially asspecified. GEo. It. HAZEW'ELL,

3. The combination of the cylinder G,jacket WM. A. MAIN.

